<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title></title>
</head>
<frameset rows="25%,*">//这个的*号相当于1-25%
  <frame src="frame1.html">
     <frameset cols="15%,*">
         <frame src="frame2.html">
         <frame src="./project/index1.html" name="frame3">
     </frameset>
</frameset>
</html>